In another public-transport episode, a friend in Xiamen witnessed an old man standing in the front of a bus, near the driver’s seat, facing the passengers with a “反台独促统一” (Oppose Taiwan independence, support national unification) sign and chanting. The passengers seemed unfazed.
My friend’s interpretation was that the man must have some deeply personal relationship to Taiwan. But I wonder if the old man was simply one of those who like (or are compelled to) rant amd rave in public places. Choosing this particular slogan, which no one can oppose, then makes sense. So he might be just like the overseas students we wrote about: as Zhang Juan suggested, patriotism is the safest and most appropriate way of any public display, not excluding those by deranged old men.